The fire marshal said there was a party at the third-floor apartment and people were jumping up and down, causing the floor to collapse.
Fire Department Battalion Chief Brian Glenn says at least 30 people were in the unit when the floor in one room collapsed. Some people drove themselves to the hospital.
The collapse prompted the building's sprinklers to go off, so the belongings of many students who lived there are now ruined. I told my roommate, 'We're leaving.
"A vast choice of amenities and its friendly staff create a worry-free environment that allows residents to focus on the most important thing - being a successful college student", according to the complex website.
"I grabbed my keys, my wallet and I left to the police department", she said.
About 50 people were packed inside for a University of North Texas homecoming after-party, jumping up and down and dancing, when the foundation buckled.
Carley Carroll, a sophmore at UNT, also lives in the badly damaged unit. Soon, multiple frantic calls flooded 911 saying a roof had collapsed.
Carroll and her three roommates, all North Texas sophomores, were not home at the time.
No one is being allowed back into Building One of the complex tonight.
It happened just before 2:00 a.m.at The Ridge at North Texas apartments located near Highway 288.
Investigators are working to figure out what caused the structural failure.